Vacuum cleaner



Nov. 1, 1938.

J. F. R. KARLSTROM VACUUM CLEANER Filed NOV. 5, 1936 2 Sheets-SheetI l N0V-,1, 1938- J. F. R. KARLsTRoM y 2,135,036

VACUUM CLEANER` Filed Nv. 5, 193s 2 sheetssheet 2 ATTORNEY.

Patented Nov. 1, 1938 UNITEDv STATES VACUUM CLEANER Johan ,FredrikRobert .Karlstrom, Bo, Sweden, assignor to Electrolux Corporation,Dover, Del., a corporation of Delaware Application November 5, 1936,Serial No. 109,241 In-Germany November 8, 1935 14 claims.' (01.183-35) AMy invention relates to vacuum cleaners. Heretofore it has been thecommon practice to provide a vacuum cleaner with a dust bag or otherdust separating member through which all of the air is forced to pass.This dust separating member not only imposes a resistance to the flow ofair, thereby decreasing the efficiency of the vacuum cleaner, but inorder that this resistance shall not rise beyond permissible limits asdust accumulates, it .has been necessary to make the dust bag many timeslarger than would be required to accommodate the necessary volume ofdust. In other Words, the size of the dust bag is determined by thepermissible resistance to ilow of air rather than by the volume of thedust accumulated.

One of the objects of my invention is to provide an eicient anddependable arrangement for separating dust `from air which involves nodust bag at all, or a dust bag of only suicient size to accommodate thedust accumulated.

Further objects and advantages of my `invention will be apparent fromthe following description considered in connection with the accompanyingdrawings, which form part of this specication, and of whichz- Fig. 1 isa cross-sectional view of one embodiment of my invention;

Fig. 2 is a. cross-sectional view line 2-2 of Fig.. 1;

Fig. 3 is a cross-sectional view of another embodiment of my invention;

taken on the Fig.V 4 is a cross-sectional view of a still fur-v therembodiment of my invention, and

Fig. 5I is a cross-sectional view taken on the line 5-5 of Fig. 4.

Referring fmore particularly to Fig. 1, reference character IDdesignates the lower part of a' vacuum cleaner housing mounted on wheelsor casters II. One end of housing I is formed as 'a suction nozzleopening I2 which is located adjacent to the surface supporting thewheels II. A drawer I3 is removably positioned within housing I0 and isprovided with a handle I4 by which it may be removed.

A hollow conical member I is secured to housing I0 and is provided atits upper and smalerv inlet opening 2|) to the impeller.

Disposed within conical member I5 is a second conical member 25, thewalls of members I5 and 25 preferably vbeing substantially parallel.Member 25 is formed with a plurality of slits 26 and preferably guidevanes 21 are provided adjacent to these slits. As will be seen from Fig.2, these guide vanes are so directed as to divert air rotating in aclockwise direction within member 25 to pass through the slits 26. Itwill be seen that conical member 25 is disposed between impellers I8 andthe smaller end of conical member I5.

A third conical member 2B is secured to the lower end of motor I'I withits smaller end below its larger end and extending upwardly into thespace within conical member 25. The housing of motor I'I is providedwith openings 29 at the lower end and openings 30 at the upper end topermit passage of air through the motor. Openings 29 are disposed withinconical member 28. The upper end of the motor is enclosed within a capv3| formed with outlet openings 32. If desired, a filter 33 may bedisposed Within the space enclosed within cap 3|.

A passageway 34 extends radially outwardly through conical member I5 ata point adjacent to impell'er I8 therein. rA dust bag 35 is secured withits interior in communication with passageway 34 by means of a flange36. A handle 31 ls plvoted to housing I0 and serves for moving thevacuum cleaner over the surface to be cleaned.

The operation of the above described device is as'follows:.-

Rotation of impeller I8 by motor II causes air to be drawn in throughnozzle opening I2 and As the vacuum cleaner is passed over a surface tobe cleaned, dust and other particles of dirt will be drawn in with thisair. In passing through screen 2I any large particles such as matches,needles and pins or the like will be separated from the air and fallinto drawer I3. 'I'he ordinary particles of dust and dirt pass throughthe screen and are acted upon along with the air by the impeller. Thisimpeller not only produces flow of air through 'the vacuum cleaner, butimparts to the air and dust discharged therefrom a. vvery rapid circularmotion which results in centrifugal force acting on the particles. Therotating air and dust in seeking an outlet from the cleaner, is forcedto pass upwardly along the inner wall of vconical l member I5 in ahelical path. However, the dust particles having a much greater massthan air molecules, the effect of centrifugal force upon the former ismuch greater than on the air and causes the dust Ato spiral vdownwardlywithin maximum diameter.

member I5 in seeking a circular path of maximum diameter. The heavier ofthe dust particles hence travel in a path having an axial directionalcomponent opposite 'to that of the air to the point of maximum diameterwithin conical member I5 and are carried radially outwardly throughpassageway 34 which communicate with the interior of conical member I5at its point of A comparatively small percentage of the air passingthrough the cleaner also paes through passageway 34. This air and dustpasses into dust bag 35 where the dust is entrained and the air passesthrough the material of the bag to the atmophere. Due to the fact 'that'only a small percentage of the total quantity of air passes through thebag, the resistance to the flow of this air is not great, even thoughthe bag is substantially full of dust. Consequently,.the size of the bagneed only be sumciet to accommodate the volume of dust and need not bedesignated extra large for the purpose of reducing resistance to airflow.

The air and lighter particles of dust are forced to spiral upwardlywithin member I5 until they strike the end wall I6 and are then forcedtov spiral downwardly around the outside of conical member 25 and passaround the lower open end of this member into the interior thereof. Muchof the dust still entrained with this air will` be thrown radiallyoutwardly when the air is forced to pass to the interior of member 25and will join the air discharged from the impeller and will again besubjected to the centrifuging action tending to cause it to pass to theplace of maximum diameter within member I5 and thence through passageway34 to the dustbag.

Dust whichY still accompanies the air around the lower end of member 25makinga second pass in an axial direction away from impeller IB` isagain subjected to a similar action within this member as was describedin connection with member I5. However, due to the provision of slits 26and vanes 21 this dust will pass outwardly through the slits and beagain subjected to a centrifuging action in the space between conicalmembers I5 .and 25.

it is forced to spiral downwardly around motor decreasing diameter.

I1 and into conical member 28. Within member 28 centrifugal force actingon any remaining dust causes it to spiral upwardly along the inner wallof the member and to pass therefrom to the stream of air spiralingupwardly Within member 25, where it will again be subjected to acentrifuging action. The air thus freed in successive passes in the samedirection from dust passes through openings 29 into the motor housing,where it serves to cool the motor and is discharged through openings 30,filter 33, if one be provided, and openings 32 to the atmosphere. Filter33 may be impregnated with a disinfectant for killing any germs whichhave such a small mass that they are not separated from the air bycentrifuging.

It will be noted that the air in flowing from the impeller to theopenings 29 in the motor is caused to travel in a spiral path ofgenerally Consequently, the further the air goes from the impeller,assuming it to travel with aconstant linear velocity, the greater mustbe its angular velocity. The angular velocity -of the air immediatelyafter it has left the impeller is suiiicient to separate the heavierparticles, while the lighter particles are/separated as the angularvelocity of the air increases.

The embodiment shown in Fig. 3 differs from that shown in Fig. 1 in thefact that the dust bag is replaced by a settling chamber formed in thedrawer I3. A partition 40 divides the drawer into atray 4I and asettling chamber 42. Passageway 34 communicates with one end of thesettling chamber, while partition 40 is provided with a restrictedopening 43 which establishes communication between the settling chamberand the inlet 20 to the impeller.

Also, in this embodiment the third conical member, here designated byreference character 28a is mounted to rotate with impeller I8. Aspreviously explained, the angularv speed of the air increases as itpasses through the device due to the decrease in the diameter of thecircular path which it is forced to follow.' However, the frictionalresistance to the flow of air may tend to prevent this increase. Bycausing the conical member, such as member 28a, to rotate in the samedirection as the air this frictional loss may be eliminated.

In operation, the dust and small quantity of air passing throughpassageway 34 as explained in connection with Fig. 1, passes intosettling chamber 42. Due to the great cross-sectional area of thischamber as compared with that of passageway 34, the velocity of' air owthrough the chamber is greatly reduced and most of the dust settlestherein. The nir and a small amount of the lighter particles which donot settle pass through opening 43 and join the stream of 'clust ladenair which pass to the impeller through inlet 20.

In Fig. 4, an embodiment of my invention is shown in conjunction with avacuum cleaner of the so-called pot" type. The lower part of the vacuumcleaner consists of a container 50 adapted to stand on 'the iioor. Thiscontainer is provided with an inlet opening 5I to which may be connecteda flexible hose leading to a suction nozzle, the nozzle being moved overthe floor of the surface to be cleaned while the rest of the vacuumcleaner remains stationary. 'I'he upper end of container 50 is formedwith a bell-mouth 52 within which isremovably supported conical memberI5.

The construction of the dust separating arrangement shown in Fig. 4diiers from that described in connection with Fig. 1, only in the factthat an opening 53 is provided in the outer wallof conical member I5adjacent to end wall I6. This opening communicates with a passage54,'also formed in conical memberv I5, and which leads downwardly tocommunicate with the interior of container 50. In this embodimentcontainer 50 constitutes a settling chamber.

lilso,l as seen in Fig. 5, the passageway 34 leading from the point ofmaximum diameter of conical member I5 to the settling chamber mayadvantageously be arranged obliquely, and in such a manner as to aid inthe flow therethrough of dust rotating in a clock-wise direction withinmember I5. Passageway 53 may likewise be arranged in this obliquemanner. The operation of this embodiment is as followsz- Rotation ofimpellers I8 by the 'motor causes air and entrained dust to be drawn into the container 50 through inlet 5I. Screen 2| preventsiany largeparticles from reaching the impeller. The air and entrained particlesare discharged from the impeller with a rapid rotary motion and theparticles are centrifuged in the same manner as described in connectionwith the embodimentI shown in Fig. 1. However, lighter particles whichreach the upper end of the space between conical members I and 25 maypass therefrom under the infiuenceof centrifuging action throughpassageways 53 'and'54 to within container 5U. The air admitted to thecontainer 50 along with the air admitted through passageway 34 andpassage 54 joins the main stream of air flowing through the inlet 20 tothe impeller and any dust not settling from the air is again subjectedto the centrifuging action.

While l have described three more or less specific embodiments of myinvention it is to be understood that this has been done for purposes ofillustration only, and that the scope of my invention is not to belimited thereto, but is to be determined by the appended claims viewedin the light of the prior art.

What I claim isi- 1. In a vacuum cleaner, a first hollow conical member,a centrifugal impeller disposed within said conical member and spacedannularly therefrom adjacent to the larger end thereof for causing flowof air and entrained solid particles andl for imparting rotary motionthereto, the smaller end of said conical member being spaced axiallyfrom said impeller, a second hollow .conical member within said firstconical member and disposed between the smaller end of lsaid firstmember and the impeller, the walls of said conical members beingsubstantially parallel, means forming a passageway for air from theinterior of said `second conical member to atmosphere, and -meansforming a passageway extending radially outwardly from the interior ofsaid rst conical member at a point adjacent to said impeller.

2. A vacuum cleaner as defined in claim 1 in which said second conicalmember is formed with apertures intermediate the ends thereof.

3. A vacuum cleaner as defined in lclaim 1 in which said second conicalmember isV formed with -apertures intermediate the ends thereof andincluding guide vanes disposed adjacent to said apertures and positionedso as to direct flow through said apertures of rotating particlesA fromwithinsaid inner conical member.

4. In a vacuum cleaner, a first hollow conical member, a centrifugalimpeller disposed within said corneal member and spaced annularlytherefrom adjacent to the larger end thereof for causing flow of air andentrained solid particles andl for imparting rotary motion thereto, thesmaller end of said conical member being spaced axially from saidimpeller, a secondhollow conical member within said first conical memberand 'clisposed between Athe smaller end of said first member and theimpeller, the walls of vsaid conical members being substantiallyparallel, an electric motor for driving said impellerv disposed withinsaid second conical member and formed with a passage for conveying airfrom within said second conical member to atmosphere, and means forminga passageway extending radially outwardly from the interior of saidfirstk conical member at a point adjacent to said impeller.

5. Ina vacuum cleaner, a first hollow conical member, a centrifugalimpeller disposed within said conical member and spaced annularlytherefrom adjacent to the larger end thereof for causing ow of air'andentrained solid particles and for imparting rotary motion thereto, thesmaller end of said conical member being spaced axially member disposedwithin said second memberl withthe smaller end of the third memberadjacent to the larger end of the second member and with the larger endof the third member between the ends of the second member, an electriclmotor for driving said impeller disposed within said second member andhaving one end extending into said third member, said motor/being formedwith a passage opening within said third member and leading toatmosphere, and means forming a passageway extending. radially.outwardly from the interior of said rst conical member at apointadjacent to said impeller.

6. In a vacuum cleaner, a first hollow conical member, a centrifugalimpeller disposed within said conical member and spaced annularlytherefrom adjacent to the larger end thereof for causing flow of air andentrained solid particles and for imparting rotary motion thereto, thesmaller end of said conical member being spaced axially from saidimpeller, a second hollow conicalfmember within said rst conical memberand disposed between the smaller end of said first member and theimpeller, the walls of said conical members being substantiallyparallel, an electric motor for driving said impeller within said secondconical member and having an end adjacent the larger end of said secondmember, a third conical member supported at the smaller end by vsaid endof the motor and extending into the, space between said motor and saidsecond end of said .conical member being spaced axially from saidimpeller, a second hollow conical member within said rst conical memberand disposed between the smaller end of said rst member and theimpeller, the walls of said conical members being substantiallyparallel, an electric motor for driving said impeller within said secondconical member, and-having an end adjacent the larger end of said secondmember, a third conical member mounted for rotationA with said impellerand having its larger end disposed within the space between said motorand said secondl member, said motor being formed with a passage openingWithin, said third member and `leading to atmosphere, and means forminga passageway extending radially outwardly from the interior of saidfirst member` at a point adjacent to said impeller.

8. In a vacuum cleaner, ahollow member having curved inner wall surface,a centrifugal impeller disposed within said hollow member andv spacedannularly therefrom for causing ow. of air and entrained solid particlesand for imparting rotary motion thereto, means forming an inlet passagefor said impeller, said hollow memberextending axially beyond saidimpeller and the cross-sectional area of said hollow member dehcreasingat points progressively more remote axially from said impeller, meansforming a passageway for air from said hollow member to the atmosphere,means forming a settling chamber,

means forming a passageway extending radially ing rotary motion thereto,means forming an inlet passage for said impeller, said hollow memberextending axially beyond said 4impeller and the cross-sectional area ofsaid hollow member decreasing at points progressively more remoteaxially from said impeller, means forming a passageway for air from saidhollow member to the atmosphere, a removable dust drawer forming asettling chamber, means forming a passageway extending radiallyoutwardly from the interior of `said hollow member at apoint adjacent tosaid impeller and communicating with said dust drawyer, and meansestablishing communication beltween said dust drawer and said inletpassage to said impeller.

10. In a vacuum cleaner, a hollow member having curved inner wallsurface, a centrifugal impeller disposed within said hollow member andspaced annularly therefrom for causing ow of air and entrained solidparticles and for imparting rotary motion thereto, said hollow memberextending axially beyond said impeller. and the cross-sectional area ofsaid hollow member decreasing at points progressively more remoteaxially from said impeller, means forming a passageway for air from saidhollow member tothe atmosphere, means forming a passageway extendingradially outwardly from the interior of said hollow member at a pointadjacent to said impeller, and means forming a passageway extendingradially outwardly from the interior of said hollow member at a placetherein of reduced diameter.

11. In a vacuum cleaner, a first hollow conical member, a centrifugalimpeller disposed within said conical member and spaced annularlytherefrom adjacent to the larger end thereof for causing ow of air andentrained solid particles and for imparting rotary motion thereto, thesmaller end of said conical member being spaced axially from saidimpeller, a second hollow conical member within said rst conical memberand disposed between the smaller end of said lrst member'and theimpeller, the walls of said conical members being substantiallyparallel, an end wall joining the smaller .ends of said conical members,means forming a passageway extend-aL ing radially outwardly from theinterior of said first conical member at a place adjacent to saidimpeller, and means forming a passageway ex- 12. In a vacuum cleaner, ahollow member having curved inner wall surface, a centrifugal impellerdisposed Within said hollow member and spaced annularly therefrom forcausing flow of airy and entrained solid particles and for impartingrotary motion thereto, said hollow member extending axially beyond saidimpeller and the cross-sectional area of said hollow member decreasingat points progressively more remote axially from said impeller, meansforming a passageway for air from said hollow member to the atmosphere,means forming a channel extending radially outwardly from the interiorof said hollow member at a point adjacent to said impeller, meansforming a channel extending radially outwardly from the interior of saidhollow member at a place therein of reduced diameter, means forming asettling chamber, both of said channels communicating with said settlingchamber, and

- means establishing communication between said settling chamber and theinlet of said impeller. 13. In a vacuum cleaner, a hollow member havingcurved inner wall surface, a centrifugal impeller disposed within saidhollow member and spaced annularly therefrom for causing flow o f airand entrained solid particlesand for imparting rotary motion thereto,said hollow member extending axially beyond said impeller and the/cross-sectional area of said hollow member decreasing at pointsprogressively more remote axially from said impeller, means forming apassageway for air from said hollow member to vthe atmosphere, saidimpeller being formed with an inlet opening, a coarse screen disposedacross the path of flow of air to said inlet, a removable receptacle, apartition dividing said receptacle into two parts, one of said partsbeing disposed below said screen and the other of said partsconstituting a settling chamber, and means forming a passagewayextending radially outwardly from the interior of said hollow member ata'point adjacent to said impeller and communicating with said settlingchamber, said partition being formed with an opening for establishingcommunication between said settling chamber and said inlet opening.

14. In a vacuum cleaner, structure forming a separator chamber having aconical wall, said chamber being formed with an inlet adjacent to itsend of maximum diameter, means for causing flow of dust laden airthrough said chamber and cooperating with said structure to impartrotary motion to said dust laden air, a hollow conical member withinsaid chamber, and disposed between its end of minimum diameter and saidinlet, the surface of said conical member being substantially parallelto said conical wall, means forming a passageway for air from theinterior of said conical member to atmosphere, and means forming apassageway extending radially outwardly from the interior of saidconical wall adjacent to its point of maximum diameter.

JOHAN FREDRIK ROBERT KARLSTROM.

